elusiveness

from WordNet (r) 3.0 (2006)

elusiveness
    n 1: the quality of being difficult to grasp or pin down; "the
         author's elusiveness may at times be construed as
         evasiveness"

from The Collaborative International Dictionary of English v.0.48

Elusive \E*lu"sive\, a.
   Tending to elude; using arts or deception to escape; adroitly
   escaping or evading; eluding the grasp; fallacious.
   [1913 Webster]

         Elusive of the bridal day, she gives
         Fond hopes to all, and all with hopes deceives. --Pope.
   -- {E*lu"sive*ly}, adv. -- {E*lu"sive*ness}, n.
   [1913 Webster]